1. Field of the Invention
The present invention is related to a storage control apparatus, a storage system, and a control method for controlling the storage system.
2. Description of the Related Art
In connection with development in IT (Information Technology) industries, storage control apparatus have been rapidly popularized, among which disk array apparatus are typically known. Storage control apparatus have been firmly utilized as major infrastructure in order to realize storage system employed in information service centers, data centers and the like in enterprises. In current storage product markets, specific attentions have been paid to virtualization of storage systems. That is, while a plurality of storage control apparatus are connected via a network to each other under communicatable condition, since the entire storage system is managed in a unification manner, resources held in the respective storage control apparatus may be effectively used (see JP-A-2002-288105).
On the other hand, among data which are managed in storage systems, there are such data which are required to be stored during a predetermined term due to natures of these data. For instance, data of account books in accounting systems and clinical histories in medial business systems must be stored for predetermined terms due to legal responsibility. Although there is no such a legal responsibility, preselected data should be stored for a predetermined term because of rules employed in organization. For example, in customer managing systems, customer data and sales data must be stored for a long time duration due to a purpose of history management.
In order to store data which are required for such a long preservation, for example, these data are stored into storage media such as magnetic tapes for back-up purposes at proper timing. However, storage media such as magnetic tapes own the following problems. That is, generally speaking, such storage media necessarily require lengthy data reading/writing time, so that rapid data processing operations could not be realized. Further, in order to read/write data with respect to such a storage media, e.g., magnetic tapes, data reading/writing apparatus are required. There is another problem as to managing workloads of such data reading/writing apparatus, and cost matters thereof. Also, since both a place for storing the storage media and a place for installing data reading/writing apparatus must be secured, there is a further problem that spaces cannot be effectively utilized.